Collison, A.J.C., Anderson, M.G. and Lloyd, D.M. (1995) Impact of vegetation on slope stability in a humid tropical environment: a modelling approach. Proc. Inst. Civil Eng. Water Maritime and Energy, 112, 168-175,. (This paper was awarded by the Institute of Civil Engineers Trevithick Premium Triennial award for a research paper to the Institution in 1996).